The subject matter herein relates generally to terminal crimping machines for crimping electrical terminals to conductors of a wire, and, more particularly, to crimp assemblies for terminal crimping machines.
Terminal crimping machines have long been used in the connector industry to effect high-speed mass termination of various cables. It is common practice for the terminal crimping machine to have an interchangeable tooling assembly called an applicator, and a powered mechanism called a terminator. In general, such terminal crimping machines are referred to as a terminator or press, however other types of terminal crimping machines may similarly be used, such as a lead maker, a bench machine, or a hand crimping tool. The terminal crimping machines include crimp tooling and an anvil that are moved relatively closer to one another during a crimping stroke to crimp a terminal or connector to an end of a wire. Typically, the anvil is stationary and the crimp tooling is driven toward and away from the anvil during a crimp stroke.
However, these known terminal crimping machines are not without disadvantages. For instance, during crimping a phenomenon known as flashing may occur when the terminal is not precisely aligned with the anvil. Flashing results in a portion of the terminal leaking past the supporting surface of the anvil and creeping down the side of the anvil. Typically, due to manufacturing tolerances, the anvil is narrower than the crimp tooling to allow clearance between the sides of the anvil and the crimp tooling. During the crimping process, the base of the terminal rests upon the anvil and is flattened out and forced into base corners. When enough force is applied, and the clearances are large enough relative to the terminal stock thickness, flash will start to occur. As flash is starting to form, the crimp tooling can and sometimes will shift to one side or the other with respect to the anvil. This shift maximizes the clearance to one side allowing more flash to occur. Flashing degrades the integrity of the crimp and may lead to crimp edge shear, which significant weakens the crimp. Flashing and crimp shear are exaggerated when crimping relatively small terminals to wires because the tolerances are larger relative to the overall size of the terminal and stock thickness of the terminal.
Typically, terminal crimping machines have crimp tooling with inner walls that have a radiused lead-in to the forming portion of the inner walls. The inner walls are angled away from one another at a crimp angle typically between approximately 3° and 6°. The crimp angle and radiused lead-in allow the terminal to be released alter crimping due to the outward taper of the terminal and the crimp tooling below the terminal. However, the radiused lead-in and crimp angle define the amount of clearance between the crimp tooling and the anvil. A proposed solution to the flashing problem is to reduce the clearance between the anvil and the crimp tooling. To do this, the lead-in radius and the crimp angle are reduced. However, additional problems arise when reducing the lead-in radius and the crimp angle. For instance, the terminal tends not to release from the crimp tooling when the lead-in radius and the crimp angle are too small, which may lead to shutdown of the terminal crimping machine to remove the terminal by hand. The crimp tooling and/or the anvil may be damaged if the terminal is not fully removed prior to the next crimp.
An additional problem associated with conventional terminal crimping machines is the phenomenon known as terminal spring back. During the crimping process, the terminal is formed around the wire by pressing the terminal inward toward the wire. The crimp tooling and anvil form a terminal base and side walls or wings that extend from base corners. The wings are folded over toward the wire. After the tooling is released, the stresses of the terminal tend to force the wings to spring back and rotate outward away from one another reducing the grip or normal force between the terminal and the wire and/or between the wings themselves. The spring back degrades the quality of the crimp.
A need remains for a crimp assembly for a terminal crimping machine that is capable of forming quality crimps. A need remains for a crimp assembly that reduces flashing and allows the terminal to release from the crimp tooling. A need remains for a crimp assembly that reduces problems associated with outward spring back of the wings of the terminal after the terminal is formed.